Call-distributing system



L PDLINKQWSKY. GALL msmuma SYSTEM. AIUPLIGA'IIOILFILED AAlJlJf Hi, 1918f 1,340,979. Patented May 25, 1920. y

' Q l N /H Ven for.'

errar LPA POLINKOWKY, 0F HYDE PARK, LONDON, ENGLAND, ASSIGNOR T0 WESTERN' v ELECTRIC COMPANY, INCORPORATED, 0F NEW YORK, 1\T. Y., Ay CORPORATION OF NEW YORK.

CALL-,DISTRIBUTING- SYSTEM.

Lafrance.'

specification@ Letters raient.

Patented May 25, 1920.

Application filed lTilly 16, 1918. Serial No. 245,222. I l

To all whom ift may concern:

Be i known that l, LirA PoLiNirowsirY, a citizen of Russia, lresiding at 70 lVestbourne Terrace, Hyde Parli, London, YV., England,

`have invented certain new and useful lmprovements in (lalLDistributing Systems, of

which the following is va full, clear, concise, andexact description.

This invention relates to call distributing systems, and more particularly to call distributing systems for semi-automatic telephone switching systems, and provides that in a system where normally calls may be eX- tended only to idle operators, apportioning means is 'brought into action upon the initiation of calls which find no idle operator accessible thereto .to extend such calls to an operator, whether busy or idle, and prevent the holding up of calls ofthe existence of' which the operators or supervisors of the exchange are in ignorance.

A particulai feature of the invention involves the busy guard on an operators posi tion being removed immediately upon the incoming of a call which finds no operators position accessible thereto.

A further feature of the invention pro' vides for automatic discrimination with regard to the operators who will be accessible to such call, one form oftthe invention providing that, as a preliminary, only such operators will be rendered accessible vto such call' as have at that time but a single call extended. thereto which has not as yet reached a predetermined stage in its extension.

A still further feature of the invention provides that under certain conditions, a. further disabling of the busyguard will take )lace on the various oieiatois-oositions and, in accordance with one form of the invention, this disablement of the busy guard,

which results in theappoitioning of an additional call to such positions, takes place regardless of the number of kcalls at that time connected to the operators position, which have not asyet received attention from such operator;

A further. feature of the invention, relatingA tothe feature above mentioned, involves the apportioning apparatus, that is, the apparatus by which the busy guard upon the various operators positions is disabled, op-

erating in` a cycle and continuingto operate apportioning a further call to each operators position so long as the condition which initiated its operation maintains.

Still another feature of the invention relates to an improved arrangement of circuits and apparatus for the timing of' the period for which the busy guard will be maintained upon an operators position and in a specific form provides for a form of `timing apparatus which' is readilyadapted to be rendered ineffective as may be required when the 'apportioning means referred to hasbeen set in operation.

Still another feature of the invention provides for the specific timing arrangement whereby the apportioning apparatus operates first to apportion calls to' such operators as are best in the position to handle such calls, that is, in accordance with the 'discriminating function of the apportioning apparatus above referred to, and, subsequently, after a definite delay, causing the apportioning of a call toall of .the operators positions, providedthe condition which has brought about the operation of the apportioning of the apparatus is still maintained.

Further features of the invention will sufliciently appear from the description of the embodiment thereof.

The accompanying figure of the drawing shows one embodiment of the invention.

A description of the invention, as disclosed. in the drawing, will be best given by a defirst line finders having access to the line l0 and places the testing potential upon the test contact 13 individual to such line in suoli first lin'e'finders. y'T he first line finders which comprise the usual power magnet 14, test relays 15 and 17, interrupter 19 and holding Amagnet 20, operate to select `and one of them seizes the calling line 10 in the usual manner, the energization of the test relay 15 in so doing placing selectable potential upon the test terminal 21 ofthe trunkline associated with such first line finder in the second line finders having access'thereto and also causing the energization of the pilot relay 22 to cause the initiation of the operation of the idle second line finders having access to this trunk line in the well known manner. These second line finders, which each comprise tne usual power magnet 211, test relays 25 and 27 and interrupter 26, are set in motion, if idle, by the energization of the relays 28 individual respectively thereto by the energization of the pilot relay 22. Whether or not the relay 23 of any given second line finder will be energized depends (1) on lwhether such second line finder and the connecting circuit individual thereto are already in use, that is, whether the sequence switch 50 associated with such circuit is out of its normal position and (2) on whetherl the timed busy guard on this operators position is effective or not, that is, whether the sequence switch contact 133 is open to render such busy guard effective or is closed to allow further calls to lcome in on such operators position.

It should be noted that on the drawings the sequence switch contacts shown in any larea circumscribed by dotted lilies forni a part of and are operated by the sequence switch indicated within such area. These sequence switches are of well known and usual construction and the operation of their contacts is in the usual` manner. Furthermore the indication on the .drawings of'the positions in which such sequence switch contacts are opened and closed is in the manner well known in the published art and need not be described in detail herein.

Furthermore the heavy dotted lines upon the drawings divide apparatus individual to different operators positions, that is, the

apparatus and circuits shown to the left of the drawing above the dot and dash line is individual to one operators position. The apparatus between the first and second heavy dotted lines such as the relays157 and 158 are individual to a second operators position and so on, the third and fourth loperators position being merely indicated.

The apparatus on the lower part of the drawing and separated from the other apparatus by the dot and dash line is common to a plurality of operators positions and may be, if desired, common to the entire exchange. hereinafter.

Assuming that the second line finder indicated and its connecting circuit are idle and that the operator on whose position such,

connecting circuit appears is also idle, the energization of the pilot relay 22 causes the energization of the guard relay 30 to prevent the illumination of the guard lamp 31, such guard relay and guard lamp being common to all of the second line finders having ac- Its function will beinade clear` cess to the trunk line of the first. line finder taken for use and alsocauses the energizav tion of the relay 23. This causes the second line finder to be started in motion to select and it will be presumed this second lineA finder seizes the trunk line taken for use,

in which operation the test relay 27 is enerr gized (1) to cause the stopping'v of the sec ond line finder in the usual manner, (2) to move the sequence switch 50 out of its first into its fourth position,andi (8) to cause the eneigization of the relay 28. In the fourth lecting sequence switch 90 in the well known Y manner, such, for instance, as described in United States patent to L. Polinko'wsky, No. 1,160,447, of November 16, 1915. This sequence switch 90 will be energized by current fiowing over the relays 107 and108. in

parallel, sequence switch contact 5 7, back contactand armature of the relay 27 which and armature of the relay 28 which relay is maintainedenergized in the fourth and fifth positionsl of sequence switch 50 by any suitable means, as for example by a circuit including sequence switch contact 56 and.

the back contact and armature of the supervisory relay 29.

The relays 107 and V108 which, as are indicated, are common to this operators position are so adjusted that the relay 107 alone will be energized if but a single equipment searching sequence switch is included in circuit therewith, whereas both said relay 107 and the relay 108 will be energized if two or more of such switches 90 are at the same time in circuit therewith, that is, if but a single call extended to a connecting circuit on this operators position has not as yet found and seized an idle registering and controlling equipment of 'this operator the relay 107 alone will be energized, whereas, if a plurality of calls extended to the connecting circuits of this operators position havenot as yet found and seized idle equipments of this operator both of said relays 107 and 108 are energized.

Meanwhile upon the energization of the relay 28, as above described, the relay 92 was energized closing over its right armature a circuit including the sequence switch contact 102 to move the sequence switch 100 out of its first into its third position. The relay 92 closes at the same time over its left armature a circuit including the sequence switch -contact 122 top to drive the sequence switch 120 out of its first and into its sixth position As the sequence switch 120 came into its uwas deeriergized when`the sequence switch 50 left its third position and Vfront contact iolo second position it closed a circuit including the sequence switch contactsk 123 top andl 132 ltop to drive the sequence switch 130 out of its first and into its sixth position. v.In

leaving its first position the sequence switch 130 opens thevsequence switch Contact 133 of which there is one of such sequence switch contacts individual to all of the connecting lcircuits uponthis operators position open= and rendering such operators' position busy and inaccessible to further incoming calls .until'such sequence' switch 130 comes again into its ,first or normal position in which such sequence switch contacts 133 are again closed. Y, In thenormalcourse suchsequence switchv 130 would be restored to its normal position when the sequence switch 100 returns to its first or normalposition in which position the rsequence switch Vconta ct 104 bottom is closedl to drive the sequence switch 120 out of its sixth into its first or normal position, the

i sequence switch contact 122 bottom being f se gclosed yat 'this time, the restoration of the sequence rswitch 1207130 itsv normal position closing'acircuitfthigl 'thesequence switch i' contacts 123 bottom and 132 bottom to drive` the sequence switch 130 out of itssixth poposition.

vAssuming that the incoming call inA dues-y tion has-immediately been connected by the' sequencefswitch 90y to. an idle registeringv and controllingequipment,test relays 25 and 27 havingbeen operated in the /well' known manner, the circuitfor the switch I90 .and the relays 107` and 108 isv open at the back contact ofthe test relay 27 and the sequence switch 50 is driven out of its fourth and fifth position and thecall relay 107 being denergized a circuit is es'- tablished overtliev armature and back cQntact of such' relay andthesequence switch contact 106 to initiate the movement of the *sequence switch 100`to its normal position and the? consequent restoration of the sequence switch '130 yto its normal p0-A sition, as has been4 described, to remove the timed busy guard control by the sequence switch contacts 133 from this operators position. The time interval for vwhich. such busy guard is maintained'will progresses from this point on in the well'known main-- ner which need not be described herein.4 Therefore,'immediately that the sequence switch 100 comes into its lsixth position the y quence switch 120 has reached its normal po sition. y y l 'As shown, the sequence switch 100 on leaving its first position stops in its third position in which position it will remain unt til as the intnerinupter 110 revolves the relay `v109is energized to drivei the sequence switch 100 out of its third position and into its,

Yfourth position `4'nver a circuit including the armature andlfront contact of such relay.

The interruptor 110, which may be com mon to the exchange, is arranged to energize the relay 109 for but a brief period, so that the circuitfor energizing the relay 109 when the sequence switch 100 is in its third position willvbe opened before such/circuit is '.again closed -at the. sequence switch contact 105 bottonfintlie fourth position. The sequence switch 100 will remain in its fourth 'positionuntilthe interrupter 110 has again 'closedthef'circuit,of the relay 109 when it willbeinoved into its fifth position where it i'villsimilarly remain until, Aduey to a fur- '.therxenergization of l,the relay 109, it is drivenfintoxits sixth position, when it will be c c ontiolledfby the d'energized condition of theielay ,107 as has been hereinbefore described.Y

Let it now'be lassume'dthat upon the venergization'of the test relay 15 and the consek quent nergization ofthepilot relay 22 in sition to come to rest in its first or normal finders having access to the trunk line eX-f the extension Vof'a call all of the second'line associated respectively with such second line f finders-were opened. i

The preferred distribution of'connecting` circuits upon operators positions is well known andv vwill be but briefiy described. The second? line finders are arranged in groups, eachl group having access to a group' ofitrunlr lines' leading to a group of first `line finders. Each group of second line finders is divided jinto a plurality of such groups, preferably of three' or moreeach,

such sub-groups severally appearing upon a plurality of operators positions, so that" each operator accessible over a'plurality of sub-groups of secondline finders will be accessible from a large number of first line finders and to a very large number of'calling lines. #Y

IIn the case last 'assumed on the various busy operators positions one or both of the vrelays 107 and 108 'may be energized, such energization preventing the restoration of .the sequence switch 130 to normal even though the sequence switch 100 has come into, its sixth position,

The extension of the call thathas been ex tended tothe first line finder shown is now obviously ,impossible over the second line finders Yhaving access thereto which are already in use. Such extension is, however, possible over second line finders having ac cess thereto which are not in use but are' rendered busy by the fact that the sequence switch contact 133 respectively individual thereto is open. When, therefore, the relay 22 is energized, since no circuit exists from the front contact ofthe armature thereof to any of the relays 23, the sequence switch cony tact 52 or the sequence switch ,contact 133 of all such circuits to which the armature of the relay 22 is common being-open the relay 30 is not energized. The guard lamp 31 is consequently lighted and the slow operating relay 33 individual to this group of second line finders starting circuits energized. This relay 33, or the relay 83 equivalent thereto which is individual to some other oup of startingcircuits indicated on the rawings by the pilot relay 82, guard relay 80 and guard lamp 81, controls the starting circuit for. the apparatus common to a plurality of the operators lpositions or to the exchange, shown below the dot anddash line upon the drawing, that is, whenever an incoming call having 'been connected to by a first line findei finds all of the second line finders by which it may be extended disabled the apportioning apparatus common to the plu-l rality of operators positions is set in motion to apportion one additional call to each of such operators ,positions of which the relay 107, 157, etc., alone is energized and'to' apportion still further calls from time to time thereafter as will be hereinafter described.

The energization of closes a circuit over the sequenceswitch contact 202 to energize the relay 211. By the attraction of'gits left hand armature this relayv closes for itself a locking circuit independent of the sequence switch contact 202.

By the attraction of its right hand armature such relay causes the venergization of' the relay 212 and of the relays 111, 191, etc. The relays 111 and 191 each serve two operators positions in the manner clearly. indicated on the drawings and are all simultaneously energized upon the energization of the relay 211. yOn the operators position .shown in the left hand'corner of the drawing, it will be assumed that but a single connecting circuit is 'still unconnected to a registering and controlling equipment and that consequently the relay 108 is not at this time energized. On this position, as on all of the other positions of the plurality to which the apportioning apparatus 'iscommon in which this condition maintains, the energization of the relay 111 or its equivalent relay closes a circuit to ground in subthe relay 33A or834 stitution for the circuit usually closedovei* the back contact and armature of the relays 107 157 etc., and the sequence switch 100 is consequently moved. from its sixth position with the consequent operation of the sequence switches 120 and 130, which closes the'sequence switch contacts 133 upon such positions and permits idle second line f finders thereon having access to the first line finder to which the call in question has been extended, to search for and seize the trunk line extending to such first line'finder. As

ra result of this operationit will be obvious that each operators position upon which the condition described maintains may have connected thereto one' further call. I

The energization of the relay 212 as described prepares a circuit to be closedby the interrupter 216 to energize the relay 215. When such relay is energized, it Closes the circuit through the left winding of the differential relay 213 directto battery and through the right `winding of such relay 213, the back Contact' and armature of such relay and sequence switch 200 to battery. The relay 213 is not energized but the sequence s witch 200 is driven out of its first position and into its second position. After leaving its first position, the sequence switch 200 closes its local contact 201 in the well known manner thereby short circuiting the .right winding of the relay 213 and causing such relay to energize. This movement of the sequence switch 200 also causes the energization of'the relay-214 which will main- Q tain the relay 213 energized until the sequence switch 200 is approaching its second position, even though the v"original energizing circuit for4 the relay 213 over the armature and'front contact of the relay 215 has been broken, due to the interruption of the.

circuit of such relay in the further movement of the interrupter 216. So long asthe relay 211 and consequently the relay 212 are maintained energized, the sequence switch 200 will remain in its second4 position until the circuit for the relay 215 is again closed by the interrupter 216 when sequence switch 200 will move into its third position and will 'again move out of its third position to be restored to its normal position in the same manner, provided, of course, the relays 211 and 212 are still energized. The energization of these relays, however, depends upon the continued energization of the relay ,33 or 83 the energization of which in turn depends upon the continued existence of the condition that a calling line connected to a first line findergfinds no second line finder having access to such first line finder in condition to search for and seize thetrunk line leading thereto.

It will first be assumed that, 'the apportioning apparatus having operated to apportion a further call to each operators position on which but a single call isalready awaiting attention, the further incoming call which has brought about this operation is connected to by one of the idle second line Enders having access thereto before the sequence switch 200 leaves its 'third posi tion| and further that no other incoming calls extended to first line finders now find no second line finders available to be connect-l ed thereto. In this event, either the guard relay 30 is energized or the pilot relay 22 is denergized and either condition causes i the opening of the circuit ,which has lighted 'switch' 200.

.the guard lamp 31y and energized the slow operating relay 3,3. The relay -33 having fallen off, the relay 211 is denergized and consequently the Arelays-111, 191 and 212 are immediately denergized. The retraction of the right armature of the relay 211 closes a circuit over the sequence switchco'ntact 203 to ydrive the sequence switch 200 directly backto its `normal"position and this will take placel whether the sequence switch is in 4its second or thirdposition. The denergi- Zation of relays -111 and 191. has rendered without yeffect the' closure of the sequence switch `contacts 204', 205, 206 nd 207 in this restoring movement vof the` sequence It should be noted that the relays 33. and

83are slow to operate'.l The purpose of this 'isto prevent a temporary en'ergiZation-ofv these relays respectively while therrelays 30 and 80 are attracting theirarmatures in the lnormal operation thereof. Each time, how

ever, that a relay 33 or 83 is energized a further incoming call is apportioned to each i of the operators having but a single call eX-H tended yto a connecting `circuit on vher position to which a registering and controlling equipment hasnot as yet been connected.

,Assuming on the other hand, that, when the apportioning apparatus has been started in operation and after the time interval nec-` y essary for such apportioning` apparatus to drive the sequence switch thereof out of its third' position, the relays 2111 and 33 or S3 are stillenergize'd indicating that, in spite oftheapportioning of calls as hereinbefore described and the timed delay 'due to the cycle of `operations between the interrupter 216v and the sequence switch 200, as has been described, 'there are still calls which have been extended to firstv linefinder switches that find no second line finder switches available'to further extend them. The sequence switch 200 in passing through its vvfourth to sixth; positions in returning to normal closes the sequence switch contacts 204, 205, 206and 207. At this time, due to the energization of the relay 211, the relays 111 and 191-are energized on each operators position (according to. the assumption each operator is busy and the sequence switch 100 e thereof is either in or coming in to its sixth position) a circuit is established from sequence switch 100 through `sequence switch contact 106, sequence switch contact 204 and front contact and armature of relay 111, and such sequence switch 100 is restored to its normal condition removing the busy guard from this operators position by the closure of the sequence switch contacts 133 in the I now well understood manner, in spite of the fact that one or both of the relays 107 and 108v of such operators position are energized. It will, therefore, be seen that under thecondition assumed a further call may be apportioned to each operators position regardless of the number of calls already extended to her position which are still awaiting attention. Each such additional apportioned call,'when it has been extended to a connecting circuit on an operators position, causes the energization of the relays 27, 28 and 92l individual to such connecting circuit and causes the sequence switches 100,l 120 and 130 to move vfrom their normal positions to vreestablish the busy guard, as has been hereinbefore described. 1f, when the sequence switch 200 returns to its normal posi-l tion, all the callsextended to first line lindfers have available second line finders to exterd them, the relay 211 will be found deenergized and the sequence switch 200 will come to rest in its normal position. If, on the other hand, due to some sudden influx of calls, the condition that second line finders are not available to extend certain calls is maintained, when the sequence switch 200 reaches its normal condition, it will continue inv operation precisely as before described. Each time it passes through the fourth to sixthpositions of its cycle it disables the timed'busy guard on each operators posi-Y ators positions, means for rendering said positions busy to other calls, and means operable upon the initiation of calls when all positions are busy for removing the busy condition-to permit such calls to beextended to. busy operators positions'.

3. A call-distributing system comprising calling lines, operators positions, means for' normally extending calls only to idle operators positions, means for'rendering said positions busy to other calls, and means operable upon the initiation \of calls when all positions are` busy for removing the'busy callin(r lines o erators ositions means for normally extending calls only to idle operators positions, means for Vrendering said positions busy to other calls, and means operable upon the initiation of calls when all positions are busy for removing' the busy condition to permit such calls to be extended to such Aoperators positions as v have at the time buta -single call extended thereto Which has not yet reached a-prede termined, stage in its extension.

6. A call-distributing system comprising calling lines, operators positions, meansfor normally extending calls only to idle operators positions, means for rendering said positions busy to other calls, means operable upon the initiation of calls When all positions are-busy for removing the busy condition to permit such calls to be extended to certain of saidbusy positions, and further means for removing the busy condition to permit calls to be extended to all of said busy operators positions.

7. A call-d'stributmg system comprising callin@r lines o erators ositions means for normally extending calls only to idle operators positions, means forv rendering said positions busy to other calls,means operable upon the in: positions are bus, for removing the busy condition to permit such calls to be extended only to such operators positions as have a predetermined. number of calls extended thereto, and means operable upon the initiation of further calls for removing t the busy condition to'permit such further calls to be extended to any of'said oper-i',

. ators positions regardless of the number of calls that has previously been extended thereto.v y

8. A call-distributing system comprising calling lines, operators positions, means for normally extending calls only to idle operi ators positions, means for rendering said positions busy to other calls, means operable upon the initiation of calls When all positions are busy for removing the busy condition to ypermit such calls to be extended only to certain of said operators tion of calls When all positions, and means responsive to the initiation of further calls for removing the busy condition to permit such further calls to be extended to any of said operators positions, said last-named means being arranged to operate in cycles and to remain veffective as long as ythere exists any unextended calls.

9. A call-distributing system comprising calling lines, operators positions, means for normally extending calls only to idle operators positions, means-for rendering said positions busy to other calls, and timing means responsive to the initiation of calls when all positions are busy for removing the busy condition to permit such calls to be extended to busy'vopera'tors positions.

10. A call-distributingwsystern comprising calling lines, operators positions, means for normally extending calls only to idle operators"po sit'ions, 'means for rendering said positions busy to other calls, timing means responsive' to the initiation of calls -When all positions are busy for removing the busy condition to permit such calls tobeV extended to certain operators positions,.and means responsive to said timingv means for removing the busy condition to permit calls kto be extended to all of said operators positions.

11. A call-distributing system comprising Vcalling lines, operatorsV positions, means 'for' normally extending calls only to idle operators positions, means for renderingeach position temporarily V*busy after acall is extended thereto, means for maintaining said busy condition at each of said positions when a denite number of, calls has been extended to such positions, and means operable upon the initiation-of calls When all positions are busy for removing the busy condition to permit such calls to be extended to busy operators positions.

12. A'call-distributing system comprising calling lines, operators. positions,means for normally extending callsonly to idle operators positions, means for rendering 'each position temporarily busy after a call is extended thereto, means for maintaining said busy condition at each of saidfpositions when' a denite number of calls has been extended to such positions, means operable upon the initiation of'callswhen all positions are busy for removing thebusy condition to permit such calls to be extendedonly to certain operators positions, andmeans responsive to the initiation of further calls for removing the busy condition to permit such calls to be extended to all said operatorspositions. f

In Witness whereof, I hereunto subscribe my name this 6th day of May A. D., 1918.

Lira PoniNKoWsKY. 

